EAGER: Exploration of Apatite Room Temperature Superconductor Phase Space

University Of South Carolina At Columbia, Columbia SC

Investigators

Abstract

Non-Technical Summary Superconductivity is a material’s ability to conduct electricity without energy loss. Only a few materials with above room temperature superconductivity have been reported, most recently in the summer of 2023. While above room temperature superconductivity is an exciting prospect, reproducing such results is challenging. With this high-risk/high-reward EAGER award, supported by the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, the principal investigator aims to systematically study the Pb-Cu-P-Si-O-S phase space, from which the most recently reported superconducting material originated. Examining the reported synthesis procedure and establishing a protocol to strategically analyze all phases of the product materials in terms of presence or absence of superconductivity creates a general blueprint for how to investigate materials systems for superconducting properties. The principal investigator engages undergraduate students in the project, which gives them the opportunity to participate in cutting-edge science that has made headlines in recent months. If an above room temperature superconductor is found, it would enable economic benefits by using such materials in the infrastructure modernization, from 1) high power transmission lines to take advantage of renewable power generation in geographically remote regions, to 2) strong permanent magnets that would remove the need for large, rare-earth-based magnets in wind turbines, and to 3) to eliminating the need for liquid helium cooling in MRI machines. Technical Summary A modified lead-apatite phase, ~Pb10-xCux(PO4)6O, created via the reaction between Cu3P and Pb2SO5, has been reported to exhibit above room temperature superconductivity. While the reported synthetic approach is unusual, it has sparked discussions whether phases with room temperature superconducting properties can be found within the complex elemental phase space, Pb-Cu-P-Si-O-S. With this high-risk/high-reward EAGER award, supported by the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, the principal investigator studies this copper doped lead apatite system, where, in addition to the copper occupying some of the Pb sites, it is necessary to consider both S occupying the oxygen site in the channels as well as the potential that some Si might have substituted for P in the PO4 groups. Isolating the original composition and determining the structure of the superconducting phase is a starting point to establish its reproducible synthesis. More generally, the development of a strategic approach to synthesize and characterize superconducting phases can support the creation of a predictive theory of superconductivity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.